Physical Sciences and Mathematics Commons^™

Giant Beaver (Castoroides) Palaeoecology Inferred From Stable Isotopes, Tessa Plint

Electronic Thesis and Dissertation Repository

Stable isotope analysis was used to explore unresolved questions about the palaeoecology of the extinct Pleistocene giant beaver (Castoroides). The δ¹³C, δ¹⁵N, and δ¹⁸O of bone collagen and structural carbonate from enamel served as proxies for palaeodiet and palaeoclimate. A new baseline for freshwater and terrestrial plant δ¹³C and δ¹⁵N was utilized in a mixing model (SIAR) to assess rodent feeding niche. SIAR analysis indicated that Castoroides’ consumed a diet of predominantly macrophytes, making them reliant on wetland habitat for food. Based on isotopic data for potential …

Reframing The Mammoth Steppe: Examining Mammoth Steppe Ecology Using Carbon And Nitrogen Isotopic Compositions Of Megafauna Collagen, Rachel E. Schwartz-Narbonne

Electronic Thesis and Dissertation Repository

The Pleistocene mammoth steppe was a vast biome that stretched from northwestern Europe to central Canada. A diverse set of megaherbivore and megacarnivore species lived within this biome and there was significant ecosystem faunal and floral homogeneity. At the end of the Pleistocene, this biome disappeared, with the extinction or extirpation of many of the megafaunal species that inhabited it. This thesis reconstructs the ecology of the mammoth steppe using the isotopic compositions of carbon and nitrogen from megafaunal collagen. The reconstruction is done at a variety of ecological scales, beginning with individual animal- and season-specific isotopic studies of antlers, …

Carbon And Nitrogen Isotopic Investigations Of The Late Pleistocene Paleoecology Of Eastern Beringia, Yukon Territory, Using Soils, Plants And Rodent Bones, Farnoush Tahmasebi

Electronic Thesis and Dissertation Repository

During the late Pleistocene (130-12 ka), Beringia, a largely ice-free land located in the Mammoth Steppe Ecosystem, was home to a large grazing community of megafauna. Many of these animals, including the woolly mammoth, became extinct at the terminal Pleistocene. Assessment of the paleoenvironment, nutrient cycling and foraging ecology in Beringia should help to understand the role of climate change in their extirpation. Such information might also help to explain the curiously higher δ¹⁵N of woolly mammoths relative to other coeval herbivores.

This study assessed eastern Beringian paleoecology using stable nitrogen (N) and carbon (C) isotopic analyses of …

Origins Of Stable Isotopic Variations In Late Pleistocene Horse Enamel And Bone From Alberta, Nicolle S. Bellissimo

Electronic Thesis and Dissertation Repository

Oxygen and carbon isotopic measurements of coevally formed bone and tooth enamel bioapatite from a modern equid show that these tissues record drinking water and diet isotopic signals in an identical fashion. Hence, data for both tissues can be combined to track movement, dietary changes, and seasonal variability over the animal’s lifetime, and climatic variability over longer time periods. This tool was tested for horses using ten paired tooth and bone samples to reconstruct conditions in Alberta during the Late Pleistocene. While post-mortem isotopic alteration confounded interpretation of the results, two key findings emerged: (i) pre- and post-Last Glacial Maximum …

Late Pleistocene Climate And Proboscidean Paleoecology In North America: Insights From Stable Isotope Compositions Of Skeletal Remains, Jessica Z. Metcalfe

Electronic Thesis and Dissertation Repository

This thesis uses the carbon, nitrogen, and oxygen isotope compositions of mammoth (Mammuthus) and mastodon (Mammut) skeletal remains to reconstruct paleoclimate and paleoecology in Late Pleistocene North America. Analytical methods, sampling strategies, environmental adaptations and seasonal behaviors of proboscideans were investigated.

Reliable and reproducible results are crucial for a study of this nature. A persistent methodological problem in the isotope analysis of structural carbonate in bioapatite was solved by reacting bioapatite under “sealed vessel” conditions.

Growth rate determinations are critical for designing sampling strategies and interpreting results. Histological and isotopic measurements demonstrated variations in enamel growth …